Turbine blade

ABSTRACT

A turbine blade with convection-cooling or screen-cooling which is capable of manufacture in small sizes and consists of two hollow blade halves provided with axial internal ribs, of which at least one rib of one hollow blade half extends beyond the profile center plane into the other hollow blade half and is connected thereat with a corresponding rib extension.

United States Patent lnventor Ludwig Pirzer Vorst Bezirk Dusseldorf, Germany Appl. No. 854,987 Filed Sept. 3, 1969 Patented Dec. 14, 1971 Assignee Daimler-Benz Aktlengesellschaft Stuttgart-Unterturkheim, Germany Priority Sept. 4, 1968 Germany P 17 76 015.5

TURBINE BLADE 10 Claims, 4 Drawing Figs.

U.S. Cl 416/90, 416/97,4l6/233 Int. Cl Fold 5/18 Field 0: Search 416/90, 95, 96, 97, 231, 233, 92, 232, 233,415/115 References Cited UNITED STATES PATENTS 9/1957 Roush 416/90 X Primary Examiner-Everette A. Powell, Jr. Attorney-Craig, Antonelli, Stewart & Hill ABSTRACT: A turbine blade with convection-cooling or screen-cooling which is capable of manufacture in small sizes and consists of two hollow blade halves provided with axial internal ribs, of which at least one rib of one hollow blade half extends beyond the profile center plane into the other hollow blade half and is connected thereat with a corresponding rib extension.

PATENTEU DEC 1 4 IS'II SHEET 1 [1F 2 FIG. I

PATENTED 115mm 3 27L443 sum 2 or 2 INVENTOR LUDWIG PIRZER ATTORNEYS TURBINE BLADE The present invention relates to a turbine blade with convection-cooling or veil-cooling (transpiration cooling). Such types of blades may be cast as hollow blades whereby a core consisting of ceramic material is subsequently etched out. Also, such blades have become known in the prior art which are constructed of a solid blade core provided with grooves that is surrounded by a thin-walled casing or jacket. These prior art types of blades, however, require a certain minimum size for their manufacture. Below this minimum size only solid blades without these cooling possibilities could be made heretofore. V I

It is the aim of the present invention to eliminate this disadvantage and to create a turbine blade with convectionor veilcooling (transpiration cooling) which can also be manufactured in very small dimensions. This is realized according to the present invention by two hollow blade halves non detachably connected with each other which are provided with axial internal ribs, of which at least one rib of one hollow blade half projects beyond the profile center plane into the other hollow blade half and is connected thereat to a corresponding rib projection.

A particularly advantageous manufacture of two approximately equally large blade halves'can be achieved according to the present invention in that a connecting seam extending approximately in the profile center plane of the blade is extended on the baseplate of the bladebase parallel to the longitudinal axis thereof and passes over at its end faces into the center plane thereof.

Accordingly, it is an object of the present invention to provide a turbine blade which avoids by simple means, the aforementioned shortcomings and drawbacks encountered in the prior art.

Another object of the present invention resides in a turbine blade which is provided with cooling means regardless of the size of the blade.

Another object of the present invention resides in a turbine blade of hollow construction to permit cooling thereof which can be readily manufactured by simple means even for small blade sizes.

Still a further object of the present invention resides in a turbine blade with convectionor veil-cooling which can be manufactured also in very small dimensions.

These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing, which shows, for purposes of illustration only, one embodiment of a turbine blade on an enlarged scale of a jet-propulsion unit, and wherein:

FIG. I is a side view of a turbine blade in accordance with the present invention;

FIG. 2 is a perspective plan view of the turbine blade of FIG.

FIG. 3 is a longitudinal cross-sectional view taken along line Ill-Ill of FIG. 2; and

FIG. 4 is a cross-sectional view taken along IV-IV ofFIG. l.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, the turbine blade illustrated in the various figures is constructed as hollow blade which contains individual air-guide chambers 11, 12 and 13 (FIG. 4) which extend from the blade generally designated by reference numeral 14 to the blade base 15. Inlet channels 16 (FIG. 3) which are arranged below the blade root 17 on each longitudinal side 18 of the blade base 15, serve for the supply of cooling air to the air-guide chambers 11, 12 and 13. Corresponding to the temperature profile of the blade 14, very small apertures 20 of different diameters for the air discharge are distributed over the entire outer surface 19 thereof, of which a few are illustrated in FIGS. 3 and 4. The sievelike interrupted surface 19 enables the formation of an air-screen or air-veil which cools the thermally, highly loaded surface of the blade l4.

The turbine blade is welded together from two hollow blade halves 21 and 22 (FIGS. 3 and 4) made on precision castings. The connecting seam 23 (FIGS. 1, 2 and 3) extends approximately in the profile center plane 24 of the blade 14 and is extended on the baseplate 25 parallel to the longitudinal axis 26 (FIG. 2) of the blade base 15. At the end faces 27 (FIG. 1) of the blade base 15, the connecting seam 23 passes over into the center plane thereof. The hollow blade halves 21 and 22 are provided within the area of the blade 14 with essentially the same wall thickness. Axial ribs 28, 29 and 30 and rib projections 31 form the air-guide chambers 11, 12 and 13 and further subdivide the same. Simultaneously, they reinforce the blade 14. The ribs 30 starting from the hollow blade half 22 project beyond the profile center plane 24 into the other hollow blade half 21 and are welded into a continuous, uninterrupted separating wall together with the corresponding rib projections 31 at the hollow blade half 21. The welding seams 32 (FIG. 4) start from the surface 19 of the hollow blade half 21 and extend from the rib projections 31 into the ribs 30 of the hollow blade half 22. The mutually opposite ribs 28 and 29 of the two hollow blade halves 21 and 22, in contradistinction thereto, leave open between the same a small gap 33 (FIGS. 3 and 4).

Instead of being made by precision casting, the hollow blade halves may also be manufactured according to any other known manufacturing methods. Prior to the connection of the blade halves already provided with cooling air apertures, possibly the interior walls and the connecting surface are machined accurately to exact dimensions. Electron beam welding is particularly suited for the connection. However, also other connecting methods, for example, soldering or brazing may be used. The blades may be subjected subsequently for the afterfinishing of the blade profile and of the shape of the blade base to a fine finishing operation, for exam ple, by eroding, etching or electrolytic grinding.

The particular advantage of the turbine blade according to the present invention resides in the fact that also blades with convection-cooling or veil-cooling (transpiration cooling) having very small dimensions can be manufactured. Thus, the blade illustrated in the example has a height of about 25 mm. and a profile thickness of about 2 to 3 mm.

Such types of blades can be used not only as rotor blades but also as guide blades of turbines.

While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as known to those skilled in the art.

Iclaim:

l. A turbine blade with convectionor transpiration-cooling, characterized by two nondetachably connected blade halves which are provided with substantially axial, internal rib means, of which at least one rib means of one hollow blade half projects beyond the profile center plane into the other hollow blade half and is connected thereat with a corresponding other rib means, and a connecting seam connecting the external surfaces of the blade halves, said connecting seam extending approximately in the profile center plane of the blade and extending at the baseplate of the blade base parallel to the longitudinal axis of the blade base and passing over at its end faces into the center plane thereof.

2. A turbine blade according to claim 1, characterized in that the rib means form several individual cooling air chambers, of which at least the rib means connected together form a continuous, uninterrupted wall, said wall extending along the entire length of the respective rib means.

3. A turbine blade according to claim 2, characterized in that some of the manually opposite rib means terminate at a small distance from one another to form a gap therebetween, said gap extending along the entire length of the respective rib means and said gap adapted to permit air transfer to cooling chambers adjacent thereto.

nal rib means, of which at least one rib means of one hollow blade half projects beyondthe profile center plane into the other hollow blade half and is connected thereat with a corresponding other rib means, characterized in that the rib means form several individual cooling inner chambers of which at least the rib means connected together form a continuous, uninterrupted wall, said wall extending along the en tire length of the respective rib means.

' 6. A turbine blade according to claim characterized in that some of the mutually opposite rib means terminate at a small distance from one another to form a gap therebetween.

7. A turbine blade according to claim 5 characterized in that the blade surfaces are provided with small discharge apertures to permit the discharge of the cooling air.

8. A turbine blade according to claim 6. characterized in that the gaps and walls are alternated within the blade.

9. A turbine blade according to claim 5, characterized in that the rib-means comprising the walls are adapted to be welded together from the external surface of the blade.

10. A turbine blade according to claim 3. further characterized in that the gaps and walls are alternated within the blade.

i l I I 

1. A turbine blade with convection- or transpiration-cooling, cHaracterized by two nondetachably connected blade halves which are provided with substantially axial, internal rib means, of which at least one rib means of one hollow blade half projects beyond the profile center plane into the other hollow blade half and is connected thereat with a corresponding other rib means, and a connecting seam connecting the external surfaces of the blade halves, said connecting seam extending approximately in the profile center plane of the blade and extending at the base plate of the blade base parallel to the longitudinal axis of the blade base and passing over at its end faces into the center plane thereof.
 2. A turbine blade according to claim 1, characterized in that the rib means form several individual cooling air chambers, of which at least the rib means connected together form a continuous, uninterrupted wall, said wall extending along the entire length of the respective rib means.
 3. A turbine blade according to claim 2, characterized in that some of the manually opposite rib means terminate at a small distance from one another to form a gap therebetween, said gap extending along the entire length of the respective rib means and said gap adapted to permit air transfer to cooling chambers adjacent thereto.
 4. A turbine blade according to claim 3, characterized in that the blade surfaces are provided with small discharge apertures to permit the discharge of the cooling air.
 5. A turbine blade with convection- or transpiration-cooling, characterized by two nondetachably connected hollow blade halves which are provided with substantially axial, internal rib means, of which at least one rib means of one hollow blade half projects beyond the profile center plane into the other hollow blade half and is connected thereat with a corresponding other rib means, characterized in that the rib means form several individual cooling inner chambers of which at least the rib means connected together form a continuous, uninterrupted wall, said wall extending along the entire length of the respective rib means.
 6. A turbine blade according to claim 5, characterized in that some of the mutually opposite rib means terminate at a small distance from one another to form a gap therebetween.
 7. A turbine blade according to claim 5, characterized in that the blade surfaces are provided with small discharge apertures to permit the discharge of the cooling air.
 8. A turbine blade according to claim 6, characterized in that the gaps and walls are alternated within the blade.
 9. A turbine blade according to claim 5, characterized in that the rib means comprising the walls are adapted to be welded together from the external surface of the blade.
 10. A turbine blade according to claim 3, further characterized in that the gaps and walls are alternated within the blade. 